As is well known to those skilled in the art, it is possible to remove sulfides including hydrogen sulfide or mercaptans from various streams which are found in chemical plants or refineries. Illustrative of patents which disclose processes for effecting this objective are U.S. Pat. No. 3,576,738 and U.S. Pat. No. 3,932,583.
In U.S. Pat. No. 3,932,583 (the disclosure of which is incorporated herein by reference), a gas containing hydrogen sulfide and carbon dioxide is contacted with an aqueous solution typically containing sodium bicarbonate and a salt of a transition metal such as nickel chloride. During contact, the hydrogen sulfide reacts with the transition metal (which has a soluble chloride and an insoluble sulfide) typically nickel, to form nickel sulfude and sulfur in the presence of dissolved oxygen. The net aqueous mixture contains a precipitate of nickel sulfide and sulfur which may be recovered as by converting to molten sulfur.
The molten sulfur so obtained may contain (on a dry basis) typically 0.01-2.5 part, say 1.25 parts of nickel sulfide NiS and 94-100 part, say 97 parts of sulfur. Commonly there may be less than 1.75 parts of other components in the molten sulfur.
It is an object of this invention to provide a method of recovering values from this waste material. Ohter objects will be apparent to those skilled in the art.